DME/LME boils

[Wings_Fan_In_KC]

As noted, it's less about the color than it is about utilizing the hops you are trying to boil. If you boil hops in water, you will get some (read: very little) hops utilization and some (read: very little) bitterness however, once you top the water up and add the malt, any of what little you had will be diluted to the point where it's like you didn't even do a hop boil.

You must boil hops in wort with the proper gravity in order to extract the desired amount of bitterness.

[haerbob3]

One thing to keep in mind is that an AG has a much higher starting volume that needs to be boiled down. To net 5.5 - 6 gallons of wort to go in the fementer. For a 60 minute boil I generally am starting out with 8.5 gallons of wort. My pre-boil gravity is 30 to 40 points lower than my SG going into the fementer. I never really did much in the way of steeps. I did partial mashes designed to give me the necessary gravity & starting volume I needed to do a volume boil.

[Crazy Climber]

As far as being concerned about killing off beasties in the bulk extract, I have always felt that 10 minutes at 160 is enough to pasteurize anything. I feel that boiling is a nice insurance policy, but not an absolute necessity by any means.

BYO Magazine says 5 minutes above 170* F is all that's needed to sanitize malt extract. FWIW.

[mashani]

RE putting it all into the boil and color be darned to heck... You just might need to add more bittering hops if your boil gravity is high. If you plug it all into software, it will typically tell you how much hops you need to reach your IBUs at your boil gravity. This is assuming you ARE doing a true full volume boil with the boil off accounted for, so you end up at the fermentation volume when done.

The 1.03-1.04 concept gives you some room there, IE if you are doing partial volume at 1.03 you get good utilization in the boil regardless of the top up later.

It's the best way to do partial volume IMHO. I make beers as good as my full volume beers by doing the 1.03 wort (sometimes even lower) for the boil and everything else as late addition at around 10 minutes.